Receptacles employing high density array of overlapping self-adjustable contacts

ABSTRACT

Connector receptacles for mating with a very high density array of male pins employ an insulating housing having female contacts mounted therein. The contacts have mating (nose) portions interconnected by relatively narrow neck portions to a mounting (body) portion. The contacts are spaced on plural levels in the direction of mating in an overlapping arrangement. In a two-level embodiment the contacts have a U-shaped nose portion with offset legs; the U-portion is formed by slotting and has contact areas comprising facing dimple bosses on opposite sides of the respective legs of the U. Alternatively the U-portion may comprise non-offset legs formed by folding. A three-level embodiment has two rows of contacts with U-shaped noses formed by bending. A four-level embodiment comprises three rows of contacts with two levels of contacts in each row and an offset-height center row. Adjacent contacts in each row have overlapping mating portions such that the neck of the upper contact passes through the U-portion of the lower contact and the mating male pin for the lower contact passes through the U-portion of the upper contact. The housings generally comprise an inner core into which the contacts are mounted; the core fits into an outer shell which has ribs for preloading the contacts. The body portion of each contact is rigidly mounted within the housing and the neck and mating portions are free to move, thereby enabling each contact to be self-adjusting to compensate for male pin misalignment.

United States Patent Ruehlemann et a1.

Apr. 8, 1975 [75] Inventors: Herbert E. Ruehlemann, Abington Twp.; JerzyR. Sochor, Upper Moreland Twp., both of Pa.

[73] Assignee: Elco Corporation, Willow Grove,

[22] Filed: Apr. 15, 1974 [21] Appl. No.: 461,183

Related US. Application Data [63] Continuation of Ser. No. 288,809.Sept. 13. 1972.

abandoned.

[52] US. Cl 339/64 M; 339/17 LC; 339/192 R; 339/207 R; 339/258 R [51]Int. Cl H0lr 13/14 [58] Field of Search 339/17 C, 17 CF, 17 LC, 339/64,206, 207, 210, 258, 259, 176, 192

[56] References Cited UNITED STATES PATENTS 2,480,059 8/1949 Stickney339/258 P 2.669.702 2/1954 Klostermann 339/258 P UX 2.757.349 7/1956Erbal 339/64 M 3.016.512 1/1962 Borchard... 339/176 M 3.086.096 4/1963McGee 339/17 LM UX 3.160.455 12/1964 Mayon et a1. 339/64 M X 3.226.66912/1965 LutZ 339/258 P X 3.486.163 12/1969 Dc Vuyst et a1. 339/258 P X3,663.925 5/1972 Proctor 339/176 MP X 3.761.864 9/1973 Sheldon 339/258 PX 3.808578 4/1974 Hansen 339/258 P X FOREIGN PATENTS OR APPLICATIONS202.268 11/1967 U.S.S.R. 339/256 RT 1,540,534 1/1970 Germany 339/258 RPrimary ExaminerMarion Parsons, Jr. Assistant Examiner-Lawrence J. Staab[57] ABSTRACT Connector receptacles for mating with a very high densityarray of male pins employ an insulating housing having female contactsmounted therein. The contacts have mating (nose) portions interconnectedby relatively narrow neck portions to a mounting (body) portion. Thecontacts are spaced on plural levels in the direction of mating in anoverlapping arrangement. In a two-level embodiment the contacts have aU-shaped nose portion with offset legs; the U- portion is formed byslotting and has contact areas comprising facing dimple bosses onopposite sides of the respective legs of the U. Alternatively the U-portion may comprise non-offset legs formed by folding. A three-levelembodiment has two rows of contacts with U-shaped noses formed bybending. A four-level embodiment comprises three rows of contacts withtwo levels of contacts in each row and an offset-height center row.Adjacent contacts in each row have overlapping mating portions such thatthe neck of the upper contact passes through the U- portion of the lowercontact and the mating male pin for the lower contact passes through theU-portion of the upper contact. The housings generally comprise an innercore into which the contacts are mounted; the core fits into an outershell which has ribs for preloading the contacts. The body portion ofeach contact is rigidly mounted within the housing and the neck andmating portions are free to move, thereby enabling each contact to beself-adjusting to compensate for male pin misalignment.

16 Claims, 12 Drawing Figures RECEPTACLES EMPLOYING I-IIGH DENSITY ARRAYOF OVERLAPPING SELF-ADJUSTABLE CONTACTS CROSS REFERENCE TO RELATEDAPPLICATION The present invention is an improvement on the inventiondescribed in the application of present coinventor Herbert E.Ruehlemann, filed 7 June 1971, Ser. No. 150,476, now abandoned.

This is a continuation of application Ser. No. 288,809, filed Sept. 13.1971 now abandoned.

BACKGROUND: FIELD OF INVENTION This invention relates to electricalconnectors and particularly a high density receptacle designed toreceive a component or module having freestanding male pins mounted in ahigh density array.

BACKGROUND: DESCRIPTION OF PRIOR ART As discussed in theabove-referenced Ruehlemann application, prior to Ruehlemanns inventionthe maxi mum mounting density in a direction normal to the direction ofmating for female contacts of a given strength and size and of the typedesigned to receive a plurality of freestanding male pins was limited bythe cross sectional area of a mated male-female contact pair, plusminimum clearance area between adjacent contact pairs. It was also notedthat as a corollary to the foregoing. it was assumed that, prior toRuehlemann. the cross-sectional area or strength of contacts of thistype, when mounted in a maximum density array, could not be increased.assuming contact material and shape were optimized.

Ruehlemann's invention, by providing contacts having wider mating thanneck or body portions and mounting such contacts in a multi-levelarrangement, provided a means of either increasing the mounting densityof contacts of a given size and strength or increasing the size andstrength of contacts mounted in what was thought to be a maximum-densityarray.

The present invention incorporates the principles of Ruehlemannsinvention, but overcomes certain limitations thereof to provide animportant improvement thereon.

In the Ruehlemann invention the density of a single row receptacle isincreased by positioning the mating portions of the female contacts indifferent levels with respect to the direction of mating and overlappinga portion of adjacent mating portions. In one embodiment Ruehlemannsuggests increasing the density of a receptacle having two staggeredrows by overlapping somewhat single beam mating portions between therows by positioning them in one row at a different level than the otherof the staggered rows. In the present invention a substantially greaterincrease .in density is achieved by providing a unique and novel designin which contacts in aligned positions between two or more aligned rowsare positioned at different levels to permit substantial overlappingbetween contacts in aligned rows. A further increase in density isachieved by positioning adjacent contacts within the same row atdifferent levels to permit their mating portions to overlap as well.

The mating or nose portions of the contacts of said Ruehlemannapplication were held relatively rigidly in the insulator housing of theconnector. Thus if a mating male pin were slightly misaligned, it wouldmeet the female contact at an off-center position, overstressing oneside of the female contact and making poor or even no contact with theother side thereof. The present invention provides a high densityreceptacle of the Ruehlemann type which can accomodate misaligned malepins.

Also, each female contact of said Ruehlemann application mated with itscorresponding male pin in one step. While not disadvantageous in otherapplications, this one step mating presents certain disadvantages in thepresent invention since a high density receptacle contains many contactswhich are mated simultaneously, so that one step mating creates arelatively high peak insertion force. The present invention provides ameans of reducing peak insertion force for a high densityreceptacle ofthe Ruehlemann type.

Additional advantages of the present invention are to provide a femalereceptacle in which the opening between the two points of contact ofeach female contact can be Zero or even negative without creatingproblems in the electroplating of such contacts during production, toprovide female contacts which can be preloaded easily by the insulatorhousing in which they are mounted, specifically by the cover thereof, toprovide contacts which are very reliable, easy to manufacture,economical, and which can be easily mounted within an insulator housing.Further objects and advantages of the present invention will becomeapparent from a consideration of the ensuing description thereof.

DRAWINGS In the drawings, where like parts are designated by identicalreference numerals, different aspects of a single embodiment aredesignated by differently-lettered versions of the same figure number,while the embodiment is referred to in the following text by its figurenumber only.

FIGS. lA-E relate to a two-tier substrate-mounted receptacle employingslotted contacts according to a preferred embodiment of the invention,together with a mating element having freestanding male pins. FIG. 1A isan isometric, cutaway view of the receptacle, FIG. 1B is an explodedview thereof, FIG. 1C is a top, cutaway view thereof, FIG. 1D is adetailed isometric view of the contacts thereof, and FIG. IE is a topview of a mated contact thereof.

FIG. 2'is a side, sectional view of a two-tier, modulemounted receptaclehaving contacts similar to those of FIG. 1 and plugged onto an array ofsubstratemounted, freestanding male pins.

FIG. 3 is a partial isometric view of a folded-nose contact according toan alternative embodiment of the invention.

FIGS. 4A, B relate to a three-tier receptacle employing folded-nosecontacts according to an alternative embodiment. FIG. 4A is a top viewand FIG. 4B is a side view of such receptacle.

FIGS. 5A-C relate to a four-tier receptacle according to an alternativeembodiment. FIG. 5A is a top cutaway view and FIG. 5B is a sidesectional view of said receptacle. FIG. 5C is an isometric, cutaway viewof the folded-nose contacts employed in said receptacle.

FIG. 1 SUBSTRATE MOUNTED TWO-TIER RECEPTACLE, SLOTTED NOSES FIG. 1 showsa preferred embodiment of the invention which comprises a receptacle 10(FIGS. 1A and IE) on a substrate 12 and designed to mate with acomponent or module 14 having a plurality of freestanding male pins suchas 16. Substrate 12 is preferrably a printed circuit board but can alsobe a metal plate or any other type of electrical wiring substrate.Pluggable module 14 (FIG. 1A) may be an encapsulated electronic devicesuch as an integrated circuit. a smaller printed circuit board or modulecard (which would have a different appearance than indicated), a ceramicwafer designed to hold an integrated circuit which is connected to themale pins. or any other electrical member from which a plurality offreestanding male pins extend in a high density array.

Receptacle comprises a plurality of female contacts such as 18 and 20(FIG. 1B) and a two-piece insulator housing comprising a core section 22and a cover section 24. Receptacle 10 is assembled by inserting contacts18 and 20 into respective slots in core 22 as indicated by the brokenlines and thereafter assembling cover 24 over loaded core 22. Asindicated, each slot in core 22 is configured to closely match the shapeof its contact 18 or 20. Cover 24 is retained to core 22 by suitablemeans (not shown for purposes of simplification) such as a detentlocking ledge, ultrasonic welding. adhesive means, force fit. etc.

Cover 24 includes apertures such as 26 in the top thereof to provideaccess to the female contacts. Cover 24 also includes preloading ridgessuch as 28 and 30 which, as explained infra, partially spread andthereby preload the mating portions of the female contacts when cover 24is assembled over core 22. Each preloading ridge has a tapered lead-inportion as indicated at 32 in order to facilitate its insertion betweenthe legs of the mating portion of the female contact.

Female contacts 18 and 20, although generally similar (FIG. 1D), havepoints of significant difference. To facilitate explanation, only uppercontact 20 will be described in detail and only those portions of lower"contact 18 which differ from corresponding portions of contact 20 willbe described. The portions of contact 18 which have identicalcounterparts in contact 20 are given identical reference numerals andpoints of difference are given primed reference numerals.

Contact 20 comprises a primary mating or nose portion 34, aninterconnection or neck portion 36, a body or mounting portion 38, and asecondary connection or tail portion 40. Nose portion 34 is designed tomate repeatedly with a male pin such as 16, neck portion 36 is designedto interconnect the body and nose portions and support nose portion 34in a flexible manner, body portion 38 is designed for mounting thecontact and holding it rigidly within insulator core 22, and tailportion 40 is designed to interconnect the contact with conductorsassociated with substrate 12, such as printed wiring on the underside ofsubstrate 12. Tail portion 40, when attached to substrate 12, also holdsentire receptacle 10 to the substrate. Tail portion 40 may take otherforms than as shown. for example it may be a press-fit portion which hasa gripping shank designed to make interference fit with a plated-throughhole in substrate 12, also it may be much longer to facilitatewire-wrapped type interconnections (trademarked Wire-Wrap), clip typeinterconnections (trademarked Termipoint). or it may be designed to beshaved on opposite sides in order to form curl portions to hold it tothe underside of substrate 12.

Body portion 38 contains a stamped dimple boss 41 which is designed tomake a press or interference fit in the bottom portion of respectiveslot of core 22. Neck portion 36 is designed to allow nose portion 34 toflex with respect to body portion 38 (according to the invention) whenthe body portion is rigidly mounted. Insulator core 22 (FIG. 1B) isdesigned to allow neck portion 36 and nose portion 34 to move to alimited extend therewithin to facilitate such flexure. In lower contact18, since nose portion 34' is much closer to body portion 38, neckportion 36 extends from one end of portion 38 in a sloping direction tonose portion 34' in order that neck portion 36 may be approximately thesame length in contact 18 as is neck portion 36 of contact 20 so thatthe nose portion 34 will be able to flex to the same extent in bothcontacts.

Nose portion 34 has a Ushaped configuration formed by slotting, i.e..removing a central strip from the nose portion to form the two legs andbight portion of the The end of the lower leg 42 of the U is integralwith neck portion 36 and the end of the upper leg 44 of the U is free.At the end of each leg of the U is a contact dimple boss as illustratedat 46 in the upper contact and at 48 at the lower contact, therespective opposing dimple bosses being similar but not visible in theillustration. These dimple bosses are designed to mate with the sides ofmale pin 16, as illustrated in FIG. 1E.

The legs of the U are spread out of the normal plane of the U (FIG. 1E)in order to enable male pin 16 to be inserted between the legs of the Uin the manner indicated. When the male pin is inserted, the legs arespread further apart and away from the normal plane of the U.

Nose portion 34 of lower contact 18 is similar to that of upper contact34, except that the upper end of neck portion 36 is attached integrallyto the bight portion of the U, rather than the end of its leg.

The bight portion of each contact has an extending boss 50 formed byupsetting; boss 50 is designed to hold upper leg 44 of the U away fromthe undersurface of the top of cover 24, thereby to allow said upper legto pivot freely during mating.

Contacts 18 and 20 appose each other when mounted in core 22 (FIG. 1Aand 1D). The nose portions of the contacts overlap in order to providemaximum mounting density, as discussed in the above Ruehlemann patentapplication. The nose portion of lower contact 18 thereby is mountedclosely adjacent the neck portion of upper contact 20. The upperandlower contacts alternate in each row (FIG. 1C also to provide maximummounting density according to the Ruehlemann principle. Thus theadjacent pair of contacts on either side of contacts 18 and 20illustrated in FIG. 1A would be reversed in relation to that shown inFIG. 1A, as illustrated in FIG. 1C.

As discussed, when contacts 18 and 20 are mounted in core 22 and cover24 is assembled thereover, preloading ridges 28 and 30 of cover 24 willbe inserted between the legs of the U portions of the nose of eachcontact and will partially spread such legs wider than theirfreestanding positions. Broken lines 52 (FIG. 1E) indicate thefreestanding position of the contact legs, broken lines 54 indicate thepreloaded position of the contact legs prior to insertion of a male pin16, and the full lines illustrated indicate the positions of the legsafter insertion of male pin 16. As is well-known, the advantages ofpreloading or partially stressing a contact prior to mating are toprovide a guaranteed minimum deflection force and thereby adequatenormal force during mating, to provide more accurate and uniform contactpositioning and thus more predictable mating conditions, to facilitateinsertion of the male pin by providing a wider spread and thus a smallerinsertion angle, and to eliminate the possibility ofcontact motion whensubjected to vibration in an unmated condition.

Since the upper and lower legs of the nose portion are staggered in thedirection of mating. when male pin 16 (FIG. 1B) is inserted it willfirst meet and deflect upper leg 44 and thereafter meet and deflectlower leg 42. Since the deflection of the upper and lower legs occurs insequence. rather than simultaneously, a lower peak insertion force isencountered. This facilitates mating, which is often difficult due tothe large number of contacts usually used in high density connectors.

Neck portion 36 allows entire nose portion 34 to move with respect torigidly mounted body portion 38. This enables both tines or legs of noseportion 34 to be deflected during mating with a male pin which is notaligned along the center or optimum axis of the female contact, wherebythe entire contact nose 34 can move to accomodate the misaligned pin. Ifcontact nose 34 were not able to so deflect, a misaligned pin mightdeflect one tine ofthe contact nose beyond its elastic limit and mightnot even contact the other tine which, as will be recognized by thoseskilled in the art, is a very undesirable condition. By allowing theentire contact nose to flex, the contact can align itself withmisaligned pins and thereby optimize mating with such pin.

FIG. 2 MODULE MOUNTED RECEPTACLE In situations where male pins aremounted on a substrate in a high density array and a modular componentis to be plugged onto such pins, the arrangement of FIG. 2 is suitable.

In FIG. 2 a plurality of male pins such as 70 are mounted to themotherboard with the aid ofa supporting substrate 72. Pin 70 may besoldered to a printed circuit line such as 74 on the underside of thesubstrate by solder 76. The lower part 78 of each pin is circular andthe upper part 80 thereof may have a cross section similar to that ofpin 16 of FIG. 1A.

A printed circuit board, a ceramic wafer, or other modular component tobe electrically and mechanically connected to pins such as 70 onsubstrate 12 is indicated at 82. A receptacle according to the inventionis similar to that of receptacle 10 of FIG. 1A, except that the tailportion of each female contact, instead of constituting a simpleelongated member, extends inwardly as indicated at 84 and contains twogripping fingers 86 and 88 which engage both sides of card 82. The tailsof all contacts are thus effectively arranged in a single row.

FIG. 3 FOLDED NOSE CONTACTS FIG. 3 shows an alternative version of thecontacts of FIG. 1A in which the nose portion of the contact is U-shaped but is formed by folding, rather than slotting. Thus the legs ofthe U are not staggered as in the FIG. IA arrangement so that the matingboss 46 of one leg opposes the mating boss (not shown) of the oppositeleg. Suitable modifications must of course be made in the contactreceiving slots of core 22 (FIG. 1B) in order to accomodate folded nosesection 90.

The arrangement of FIG. 3 is desirable in receptacles where receptacleheight is a consideration since by not staggering the legs of the U, theheight of the contact, and hence the receptacle, is significantlyreduced.

FIG. 4 THREE-TIER RECEPTACLE, FOLDED NOSE CONTACTS The folded nosecontact of FIG. 3 is used in the three-tier embodiment of the inventionillustrated in FIG. 4. In this arrangement the receptacle comprises acore 100, a cover 102, and short, medium, and tall female contacts 104.,106, and 108.

The contacts are arranged in two rows with each row containing retainingrecurring sets of short, medium, and tall contacts as indicated. Theapposing contacts of the opposite row are staggered with respect totheir counterparts of the first row and overlap the contacts of theother row, both horozontally and vertically when viewed in the directionshowed in FIG. 4A.

The arrangement of FIG. 4, by providing three tiers of contacts in thedirection of mating, reduces peak insertion force and also providesgreater wall thickness in the insulator core between adjacent contacts.

FIG. 5 FOUR-TIER RECEPTACLE The arrangement of FIG. 5 is a four-tierreceptacle in which contacts similar to that of FIG. 3, but using noseportions wherein the U is wider and has inwardly bent, parallel freeends. The insulator housing comprises three parts, a bottom (FIG. 53), amiddle portion 122, and a cover 124. These portions are suitably bondedtogether by any means well known in the art.

The nose portions of allcontacts are substantially identical, but thecontacts have four different tail lengths. The contacts are mounted inthree rows 126, I28, and (FIG. 5A) with the contacts in each row beingmounted in apposing pairs such as 132 and 134. Each apposing paircontains an upper contact 132 and a lower contact 134 wherein the leg(rather than the bight) portions of the U-shaped nose sections overlap.Thus tail 136 (FIG. 5C) of upper contact 132 passes through nose portionof lower contact 134 and the male pin 138 which mates with lower contact134 passes through the nose portion of upper contact 132. The tailportion of each contact is offset as indicated at 140 in order that tailportion 136 of upper contact 132 will pass through the center of noseportion of lower contact 134 and the tail portion 142 of lower contact134 will be aligned with the tail portion of contact 132.

Male pin 144, which is designed to mate with upper contact 132, isshorter than that of male contact 138 so that it will not contact offsettail portion 140 of upper contact 132.

The left apposing pair of contacts in row 126 (FIG. 5A), partiallyillustrated at 146, contains two contacts similar to contacts 132 and134 and arranged in the same orientation such that the lower contactwill lie on the right and its bight portion will be overlapped by thebight portion of contact 132 of the right pair of contacts of row 126.

In addition to overlapping the adjacent pair of contacts in the samerow, each pair of contacts overlaps the adjacent pair of contacts in thenext row. Thus contacts 132 and 134 of row 126 overlap the adjacent pairof contacts in row 128 immediately above contacts 132 and 134. Thecontacts in center row 128 (FIG. 5B)

are mounted at a lower elevation than the contacts in outer rows 126 and130 in order to permit such overlapping and hence maximum densitymounting.

Although only three rows of four contacts each are illustrated in FIG.A. the arrangement can be extended indefinitely with adjacent rows beingmounted at different heights and each contact of apposing pairs in eachrow being mounted at different heights, thus using contacts with fourdifferent tail lengths. This necessitates that the male pins of a matingelement 148 have four corresponding different lengths (not shown).

As in the other arrangements, the tail portions of the contacts of FIG.5 are rigidly mounted by embedding them in lower insulator portion 120and the nose portions are free to move, thereby to accomodate misalignedmale pins in a manner aforediscussed.

While the above description contains many specificities, these are notintended to limit the scope of the invention, but merely to exemplifyseveral preferred embodiments thereof. Many other embodiments accordingto the invention are possible. Accordingly the full scope of theinvention is intended to be indicated by the subject matter of theappended claims and their legal equivalents.

We claim:

1. In a receptacle including an insulator housing and two rows of femalecontacts therein for receiving a plurality of male pins arranged in tworows when said pins are moved along an axis of engagement theimprovement comprising:

positioning said female contacts in said insulator housing such that;adjacent contacts in each row are at different levels along said axisand overlap each other when viewed along said axis, the contacts of onerow are at different levels along said axis and overlap correspondingcontacts of the other row when viewed along said axis, whereby thecontacts are spaced closer together than the minimum spacing required ifsaid contacts were in the same level, each row having at least onecontact at a higher level than some contact of the other row.

2. The improvement of claim 1 wherein each of said female contactsincludes two opposing contacting members for engaging opposite sides ofamale pin, said opposing contacting members being located at differentlevels along said axis thereby reducing insertion forces.

3. The improvement of claim 1 wherein each of said female contactsincludes a mating portion, a body portion, and a supporting neck portionextending between said mating and body portions, and is formed fromsheet metal.

4. The improvement of claim 2 wherein said contacting members are formedby the legs ofa U-shaped mating portion, which lies in a plane parallelto said axis.

5. The improvement of claim 1 wherein said insulator housing includes aninner core having cavities into which said female contacts arepositioned, and an outer shell surrounding said inner core.

6. The improvement of claim 5 wherein said outer shell includes integralmeans for preloading said female contacts.

7. In a receptacle including an insulator housing and at least twoaligned rows of female contacts therein for receiving a plurality ofmale pins arranged in two aligned rows when said pins are moved along anaxis of engagement the improvement comprising:

providing pairs of female contacts, each pair having a first contactfrom one of said rows and a second contact from another of said rowssaid first contact having a mating portion at a first level along saidaxis, and said second contact having a mating portion at a second levelspaced from said first level, said pairs of contacts being positionedwith said mating portions overlapping between aligned positions in saidtwo rows when viewed along said axis, the mating portions of adjacentcontacts within each row also being in different levels, and each ofsaid mating portions including two opposing contact areas positioned atspaced levels along said axis.

8. The improvement of claim 7 wherein said mating portions of adjacentcontacts within each row also overlap when viewed along said axis.

9.-The improvement of claim 7 wherein each of said mating portions isU-shaped having two legs and a bight portion, said bight portionextending parallel to said axis, and said legs including said opposingcontact making areas.

10. The improvement of claim 7 wherein each of said female contactsfurther include neck means for flexibly supporting said mating portions,said neck means of said first and second contacts being madesubstantially the same length to provide the same flexibility by havingsaid neck means extend diagonally on one of said contacts.

11. The improvement of claim 7 wherein said insulator housing includesan inner core having cavities into which said pairs of contacts arepositioned and an outer shell surrounding said core.

12. The improvement of claim 11 wherein said outer shell includesintegral means for preloading said female contacts.

13. In a receptacle including an insulator housing and a plurality offemale contacts therein for receiving a plurality of male pins when saidpins are moved along an axis of engagement, each of said female contactshaving a mating portion with two integral opposing contact making areasfor engaging opposite sides of a male pin, the improvement comprising:

providing said two opposing contact making areas at different levelsalong said axis by forming each of said mating portions in a U-shapehaving a bight.

portion extending parallel to said axis, and two legs extendingtransverse to said axis with said legs.

being said opposed contact making areas.

14. The improvement of claim 13 wherein each of said female contactsfurther includes a body portion and a supporting neck portion extendingbetween said mating and body portions, and wherein said female contactsmay be formed from sheet metal.

neck means of contacts disposed at different levels in said insulatorhousing along said axis being made substantially the same length toprovide substantially the same flexibility by having said neck meansextend diagonally on some of said contacts.

1. In a receptacle including an insulator housing and two rows of femalecontacts therein for receiving a plurality of male pins arranged in tworows when said pins are moved along an axis of engagement theimprovement comprising: positioning said female contacts in saidinsulator housing such that; adjacent contacts in each row are atdifferent levels along said axis and overlap each other when viewedalong said axis, the contacts of one row are at different levels alongsaid axis and overlap corresponding contacts of the other row whenviewed along said axis, whereby the contacts are spaced closer togetherthan the minimum spacing required if said contacts were in the samelevel, each row having at least one contact at a higher level than somecontact of the other row.
 2. The improvement of claim 1 wherein each ofsaid female contacts includes two opposing contacting members forengaging opposite sides of a male pin, said opposing contacting membersbeing located at different levels along said axis thereby reducinginsertion forces.
 3. The improvement of claim 1 wherein each of saidfemale contacts includes a mating portion, a body portion, and asupporting neck portion extending between said mating and body portions,and is formed from sheet metal.
 4. The improvement of claim 2 whereinsaid contacting members are formed by the legs of a U-shaped matingportion, which lies in a plane parallel to said axis.
 5. The improvementof claim 1 wherein said insulator housing includes an inner core havingcavities into which said female contacts are positioned, and an outershell surrounding said inner core.
 6. The improvement of claim 5 whereinsaid outer shell includes integral means for preloading said femalecontacts.
 7. In a receptacle including an insulator housing and at leasttwo aligned rows of female contacts therein for receiving a plurality ofmale pins arranged in two aligned rows when said pins are moved along anaxis of engagement the improvement comprising: providing pairs of femalecontacts, each pair having a first contact from one of said rows and asecond contact from another of said rows said first contact having amating portion at a first level along said axis, and said second contacthaving a mating portion at a second level spaced from said first level,said pairs of contacts being positioned with said mating portionsoverlapping between aligned positions in said two rows when viewed alongsaid axis, the mating portions of adjacent contacts within each row alsobeing in different levels, and each of said mating portions includingtwo opposing contact areas positioned at spaced levels along said axis.8. The improvement of claim 7 wherein said mating portions of adjacentcontacts within each row also overlap when viewed along said axis. 9.The improvement of claim 7 wherein each of said mating portions isU-shaped having two legs and a bight portion, said bight portionextending parallel to said axis, and said legs including said opposingcontact making areas.
 10. The improvement of claim 7 wherein each ofsaid female contacts further include neck means for flexibly supportingsaid mating portions, said neck means of said first and second contactsbeing made substantially the same length to provide the same flexibilityby having said neck means extend diagonally on one of said contacts. 11.The improvement of claim 7 wherein said insulator housing includes aninner core having cavities into which said pairs of contacts arepositioned and an outer shell surrounding said core.
 12. The improvementof claim 11 wherein said outer shell includes integral means forpreloading said female contacts.
 13. In a receptacle including aninsulator housing and a plurality of female contacts therein forreceiving a plurality of male pins when said pins are moved along anaxis of engagement, each of said female contacts having a mating portionwith two integral opposing contact making areas for engaging oppositesides of a male pin, the improvement comprising: providing said twoopposing contact making areas at different levels along said axis byforming each of said mating portions in a U-shape having a bight portionextending parallel to said axis, and two legs extending transverse tosaid axis with said legs being said opposed contact making areas. 14.The improvement of claim 13 wherein each of said female contacts furtherincludes a body portion and a supporting neck portion extending betweensaid mating and body portions, and wherein said female contacts may beformed from sheet metal.
 15. The improvement of claim 13 wherein saidfemale contacts are arranged in at least one row with adjacent contactsbeing disposed at different levels within said insulator housing alongsaid axis.
 16. In a receptacle including an insulator housing and aplurality of female contacts therein for receiving a plurality of malepins when said pins are moved along an axis of engagement, each of saidfemale contacts having a mating portion with two integral opposingcontact making areas for engaging opposite sides of a male pin, theimprovement comprising: providing said two opposing contact making areasat different levels along said axis, arranging said female contacts inat least one row with adjacent contacts being disposed at differentlevels within said insulator housing along said axis, and providing eachof said female contacts with neck means for flexibly supporting saidmating portions, said neck means of contacts disposed at differentlevels in said insulator housing along said axis being madesubstantially the same length to provide substantially the sameflexibility by having said neck means extend diagonally on some of saidcontacts.